Electron positron accumulator

Electrons for LEP are easy to produce, but positrons, the antiparticle of electrons, are more tricky to make.

Energetic electrons are made to pass through a metal foil. In the collisions pairs of electrons and positrons are created.

Positrons are selected and stored in the Electron Positron Accumulator, until there are enough of them to form a beam.

The electron positron accumulator. A hundred pulses from the linear accelerator are stored in this accumulation ring before injection into the next stage, booster.